1. Field
The present invention relates to a pose estimating device and a pose estimating method for an articulated object such as a human body based on an image obtained from a camera without requiring a marker.
2. Related Art
In JP-A2001-56861(KOKAI) and JP2627483 (J. OHYA), a silhouette of an articulated object is extracted and the observed silhouette and various silhouettes obtained from a three dimensional shape model are matched by using a genetic algorithm to estimate a pose. In such a direct matching method of the silhouette, the pose may not be possibly estimated in a stable way due to the difference in length, thickness, or surface form of links connecting joints between the three dimensional shape model and the articulated object to be recognized. For instance, when the pose of a human body is estimated, since a silhouette changes due to the difference of clothes, or the difference of a physique such as a height or a weight, even when a person to be recognized and the three dimensional shape model of a human body previously provided in the device have the same pose, these silhouettes are different. Thus, the pose cannot be correctly recognized.
In related art B. Stenger, A. Thayananthan, P. H. S. Torr, and R. Cipolla, “Filtering Using a Three-Based Estimator,” In Proc. 9th IEEE International Conference on Computer Vision, Vol. II. Pages 1063-1070, 2003, relates a pose estimating method of a hand in which when a feature (edge) obtained from an image is matched with an image feature (outline) obtained from a three dimensional shape model of a hand having various poses to estimate a pose, a previously formed tree structure is used to carry out a search operation. However, outline information used herein is liable to be influenced by the difference of the length or thickness of links like silhouette information.